As a basic course of science and engineering，college physics with complete theoretical content and diversified teaching forms let students learn basic knowledge and scientific research methods. It is introduced in this paper how to develop an effective online teaching based on optimized combination of educational technologies in face of COVID-19 epidemic. The teaching team not only creates a space for students to study independently through the MOOC platform of Chinese universities，but also makes students feel a warm online college physics class through effective implementation plan ( live interaction，asking and resolving，classroom management) and multidimensional evaluation ( preview before class，interaction in class and self-test after class) .